Statistical optimization of waste molasses-based exopolysaccharides and self-sustainable bioelectricity production for dual chamber microbial fuel cell by Bacillus piscis

Microbial Cell Factories

Research

Ebtehag A. E. Sakr¹  Zeinab M. H. Kheiralla¹  Kamel M. El‑khatib²  Dena Z. Khater² 

[1] Botany Department, Faculty of Women for Arts, Science and Education, Ain Shams University, Cairo, Egypt;Chemical Engineering and Pilot Plant Department, National Research Centre (NRC), El Buhouth St., 12622, Cairo, Dokki, Egypt;

关键词: Bacillus piscis;    Optimized molasses-based media;    EPS;    COD removal;    Decolorization;    Electrochemical activity;   

DOI  :  10.1186/s12934-023-02216-w

 received in 2023-07-27, accepted in 2023-09-26,  发布年份 2023

来源: Springer

【 摘 要 】

BackgroundThe application of exopolysaccharide-producing bacteria (EPS) in dual chamber microbial fuel cells (DCMFC) is critical which can minimize the chemical oxygen demand (COD) of molasses with bioelectricity production. Hence, our study aimed to evaluate the EPS production by the novel strain Bacillus piscis by using molasses waste. Therefore, statistical modeling was used to optimize the EPS production. Its structure was characterized by UV, FTIR, NMR, and monosaccharides compositions. Eventually, to highlight B. piscis' adaptability in energy applications, bioelectricity production by this organism was studied in the BCMFC fed by an optimized molasses medium.ResultsB. piscis OK324045 characterized by 16S rRNA is a potent EPS-forming organism and yielded a 6.42-fold increase upon supplementation of molasses (5%), MgSO4 (0.05%), and inoculum size (4%). The novel exopolysaccharide produced by Bacillus sp. (EPS-BP5M) was confirmed by the structural analysis. The findings indicated that the MFC's maximum close circuit voltage (CCV) was 265 mV. The strain enhanced the performance of DCMFC achieving maximum power density (PD) of 31.98 mW m−2, COD removal rate of 90.91%, and color removal of 27.68%. Furthermore, cyclic voltammetry (CV) revealed that anodic biofilms may directly transfer electrons to anodes without the use of external redox mediators. Additionally, CV measurements made at various sweep scan rates to evaluate the kinetic studies showed that the electron charge transfer was irreversible. The SEM images showed the biofilm growth distributed over the electrode’s surface.ConclusionsThis study offers a novel B. piscis strain for EPS-BP5M production, COD removal, decolorization, and electricity generation of the optimized molasses medium in MFCs. The biosynthesis of EPS-BP5M by a Bacillus piscis strain and its electrochemical activity has never been documented before. The approach adopted will provide significant benefits to sugar industries by generating bioelectricity using molasses as fuel and providing a viable way to improve molasses wastewater treatment.

【 授权许可】

CC BY   
© BioMed Central Ltd., part of Springer Nature 2023

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